`timescale 1ns/1ps
module tb_key_led();
    reg [3:0]key=0;
    wire [7:0]led;
    key_led u1(.key(key),.led(led));
    initial
        begin
            key=4'b1111;
            repeat(10)
            begin
            #20 key=4'b0111;
            #20 key=4'b1011;
            #20 key=3'b1101;
            #20 key=4'b1110;
            end
        end
endmodule
